A presentation at the April 2019 Operation for Community Development and Empowerment (OPCDE) cybersecurity conference describes SAP systems with unsecure configurations exposed to the internet. Typically, SAP systems are not intended to be exposed to the internet as it is an untrusted network. Malicious cyber actors can attack and compromise these unsecure systems with publicly available exploit tools, termed “10KBLAZE.” The presentation details the new exploit tools and reports on systems exposed to the internet.SAP Gateway ACL

The SAP Gateway allows non-SAP applications to communicate with SAP applications. If SAP Gateway access control lists (ACLs) are not configured properly (e.g., gw/acl_mode = 0), anonymous users can run operating system (OS) commands.[2] According to the OPCDE presentation, about 900 U.S. internet-facing systems were detected in this vulnerable condition.SAP Router secinfo

The SAP router is a program that helps connect SAP systems with external networks. The default secinfo configuration for a SAP Gateway allows any internal host to run OS commands anonymously. If an attacker can access a misconfigured SAP router, the router can act as an internal host and proxy the attacker’s requests, which may result in remote code execution.
According to the OPCDE presentation, 1,181 SAP routers were exposed to the internet. It is unclear if the exposed systems were confirmed to be vulnerable or were simply running the SAP router service.SAP Message Server

SAP Message Servers act as brokers between Application Servers (AS). By default, Message Servers listen on a port 39XX and have no authentication. If an attacker can access a Message Server, they can redirect and/or execute legitimate man-in-the-middle (MITM) requests, thereby gaining credentials. Those credentials can be used to execute code or operations on AS servers (assuming the attacker can reach them). According to the OPCDE presentation, there are 693 Message Servers exposed to the internet in the United States. The Message Server ACL must be protected by the customer in all releases.Signature

The National Cybersecurity and Communications Integration Center (NCCIC), part of the Cybersecurity and Infrastructure Security Agency (CISA), is aware of a global Domain Name System (DNS) infrastructure hijacking campaign. Using compromised credentials, an attacker can modify the location to which an organization’s domain name resources resolve. This enables the attacker to redirect user traffic to attacker-controlled infrastructure and obtain valid encryption certificates for an organization’s domain names, enabling man-in-the-middle attacks.
See the following links for downloadable copies of open-source indicators of compromise (IOCs) from the sources listed in the References section below:

These files will be updated as information becomes available.Technical Details

Using the following techniques, attackers have redirected and intercepted web and mail traffic, and could do so for other networked services.

The attacker begins by compromising user credentials, or obtaining them through alternate means, of an account that can make changes to DNS records.

Next, the attacker alters DNS records, like Address (A), Mail Exchanger (MX), or Name Server (NS) records, replacing the legitimate address of a service with an address the attacker controls. This enables them to direct user traffic to their own infrastructure for manipulation or inspection before passing it on to the legitimate service, should they choose. This creates a risk that persists beyond the period of traffic redirection.

Because the attacker can set DNS record values, they can also obtain valid encryption certificates for an organization’s domain names. This allows the redirected traffic to be decrypted, exposing any user-submitted data. Since the certificate is valid for the domain, end users receive no error warnings.

Mitigations

NCCIC recommends the following best practices to help safeguard networks against this threat:

Update the passwords for all accounts that can change organizations’ DNS records.

Implement multifactor authentication on domain registrar accounts, or on other systems used to modify DNS records.

Audit public DNS records to verify they are resolving to the intended location.

Search for encryption certificates related to domains and revoke any fraudulently requested certificates.

The Department of Homeland Security (DHS) National Cybersecurity and Communications Integration Center (NCCIC) and the Federal Bureau of Investigation (FBI) are issuing this activity alert to inform computer network defenders about SamSam ransomware, also known as MSIL/Samas.A. Specifically, this product shares analysis of vulnerabilities that cyber actors exploited to deploy this ransomware. In addition, this report provides recommendations for prevention and mitigation.
The SamSam actors targeted multiple industries, including some within critical infrastructure. Victims were located predominately in the United States, but also internationally. Network-wide infections against organizations are far more likely to garner large ransom payments than infections of individual systems. Organizations that provide essential functions have a critical need to resume operations quickly and are more likely to pay larger ransoms.
The actors exploit Windows servers to gain persistent access to a victim’s network and infect all reachable hosts. According to reporting from victims in early 2016, cyber actors used the JexBoss Exploit Kit to access vulnerable JBoss applications. Since mid-2016, FBI analysis of victims’ machines indicates that cyber actors use Remote Desktop Protocol (RDP) to gain persistent access to victims’ networks. Typically, actors either use brute force attacks or stolen login credentials. Detecting RDP intrusions can be challenging because the malware enters through an approved access point.
After gaining access to a particular network, the SamSam actors escalate privileges for administrator rights, drop malware onto the server, and run an executable file, all without victims’ action or authorization. While many ransomware campaigns rely on a victim completing an action, such as opening an email or visiting a compromised website, RDP allows cyber actors to infect victims with minimal detection.
Analysis of tools found on victims’ networks indicated that successful cyber actors purchased several of the stolen RDP credentials from known darknet marketplaces. FBI analysis of victims’ access logs revealed that the SamSam actors can infect a network within hours of purchasing the credentials. While remediating infected systems, several victims found suspicious activity on their networks unrelated to SamSam. This activity is a possible indicator that the victims’ credentials were stolen, sold on the darknet, and used for other illegal activity.
SamSam actors leave ransom notes on encrypted computers. These instructions direct victims to establish contact through a Tor hidden service site. After paying the ransom in Bitcoin and establishing contact, victims usually receive links to download cryptographic keys and tools to decrypt their network.Technical Details

NCCIC recommends organizations review the following SamSam Malware Analysis Reports. The reports represent four SamSam malware variants. This is not an exhaustive list.

DHS and FBI recommend that users and administrators consider using the following best practices to strengthen the security posture of their organization's systems. System owners and administrators should review any configuration changes before implementation to avoid unwanted impacts.

Audit your network for systems that use RDP for remote communication. Disable the service if unneeded or install available patches. Users may need to work with their technology venders to confirm that patches will not affect system processes.

Verify that all cloud-based virtual machine instances with public IPs have no open RDP ports, especially port 3389, unless there is a valid business reason to keep open RDP ports. Place any system with an open RDP port behind a firewall and require users to use a virtual private network (VPN) to access that system.

Minimize network exposure for all control system devices. Where possible, disable RDP on critical devices.

Regulate and limit external-to-internal RDP connections. When external access to internal resources is required, use secure methods such as VPNs. Of course, VPNs are only as secure as the connected devices.

Scan for and remove suspicious email attachments; ensure the scanned attachment is its "true file type" (i.e., the extension matches the file header).

Disable file and printer sharing services. If these services are required, use strong passwords or Active Directory authentication.

Additional information on malware incident prevention and handling can be found in Special Publication 800-83, Guide to Malware Incident Prevention and Handling for Desktops and Laptops, from the National Institute of Standards and Technology.[1]Contact Information

To report an intrusion and request resources for incident response or technical assistance, contact NCCIC, FBI, or the FBI’s Cyber Division via the following information:

DHS strives to make this report a valuable tool for our partners and welcomes feedback on how this publication could be improved. You can help by answering a few short questions about this report at the following URL: https://www.us-cert.gov/forms/feedback.References

This joint Technical Alert (TA) is the result of analytic efforts between the Department of Homeland Security (DHS) and the Federal Bureau of Investigation (FBI). DHS and FBI are releasing this TA to provide information about a major online ad fraud operation—referred to by the U.S. Government as "3ve"—involving the control of over 1.7 million unique Internet Protocol (IP) addresses globally, when sampled over a 10-day window.Description

Online advertisers desire premium websites on which to publish their ads and large numbers of visitors to view those ads. 3ve created fake versions of both (websites and visitors), and funneled the advertising revenue to cyber criminals. 3ve obtained control over 1.7 million unique IPs by leveraging victim computers infected with Boaxxe/Miuref and Kovter malware, as well as Border Gateway Patrol-hijacked IP addresses. Boaxxe/Miuref Malware

Boaxxe malware is spread through email attachments and drive-by downloads. The ad fraud scheme that utilizes the Boaxxe botnet is primarily located in a data center. Hundreds of machines in this data center are browsing to counterfeit websites. When these counterfeit webpages are loaded into a browser, requests are made for ads to be placed on these pages. The machines in the data center use the Boaxxe botnet as a proxy to make requests for these ads. A command and control (C2) server sends instructions to the infected botnet computers to make the ad requests in an effort to hide their true data center IPs.Kovter Malware

Kovter malware is also spread through email attachments and drive-by downloads. The ad fraud scheme that utilizes the Kovter botnet runs a hidden Chromium Embedded Framework (CEF) browser on the infected machine that the user cannot see. A C2 server tells the infected machine to visit counterfeit websites. When the counterfeit webpage is loaded in the hidden browser, requests are made for ads to be placed on these counterfeit pages. The infected machine receives the ads and loads them into the hidden browser.Impact

For the indicators of compromise (IOCs) below, keep in mind that any one indicator on its own may not necessarily mean that a machine is infected. Some IOCs may be present for legitimate applications and network traffic as well, but are included here for completeness.Boaxxe/Miuref Malware

Boaxxe malware leaves several executables on the infected machine. They may be found in one or more of the following locations:

%UserProfile%\AppData\Local\VirtualStore\lsass.aaa

%UserProfile%\AppData\Local\Temp\.exe

%UserProfile%\AppData\Local\\.exe

The HKEY_CURRENT_USER (HKCU) “Run” key is set to the path to one of the executables created above.

HKCU\Software\Microsoft\Windows\CurrentVersion\Run\\

Kovter Malware

Kovter malware is found mostly in the registry, but the following files may be found on the infected machine:

The keys will look like random values and contain scripts. In some values, a User-Agent string can be clearly identified. An additional key containing a link to a batch script on the hard drive may be placed within registry key:

HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

There are several patterns in the network requests that are made by Kovter malware when visiting the counterfeit websites. The following are regex rules for these URL patterns:

If you believe you may be a victim of 3ve and its associated malware or hijacked IPs, and have information that may be useful to investigators, submit your complaint to www.ic3.gov and use the hashtag 3ve (#3ve) in the body of your complaint.
DHS and FBI advise users to take the following actions to remediate malware infections associated with Boaxxe/Miuref or Kovter:

Use and maintain antivirus software. Antivirus software recognizes and protects your computer against most known viruses. Security companies are continuously updating their software to counter these advanced threats. Therefore, it is important to keep your antivirus software up-to-date. If you suspect you may be a victim of malware, update your antivirus software definitions and run a full-system scan. (See Understanding Anti-Virus Software for more information.)

Avoid clicking links in email. Attackers have become very skilled at making phishing emails look legitimate. Users should ensure the link is legitimate by typing the link into a new browser. (See Avoiding Social Engineering and Phishing Attacks.)

Keep your operating system and application software up-to-date. Install software patches so that attackers cannot take advantage of known problems or vulnerabilities. You should enable automatic updates of the operating system if this option is available. (See Understanding Patches and Software Updates for more information.)

Use anti-malware tools. Using a legitimate program that identifies and removes malware can help eliminate an infection. Users can consider employing a remediation tool. A non-exhaustive list of examples is provided below. The U.S. Government does not endorse or support any particular product or vendor.

This report is a collaborative research effort by the cyber security authorities of five nations: Australia, Canada, New Zealand, the United Kingdom, and the United States.[1][2][3][4][5]
In it we highlight the use of five publicly available tools, which have been used for malicious purposes in recent cyber incidents around the world. The five tools are:

To aid the work of network defenders and systems administrators, we also provide advice on limiting the effectiveness of these tools and detecting their use on a network.
The individual tools we cover in this report are limited examples of the types of tools used by threat actors. You should not consider this an exhaustive list when planning your network defense.
Tools and techniques for exploiting networks and the data they hold are by no means the preserve of nation states or criminals on the dark web. Today, malicious tools with a variety of functions are widely and freely available for use by everyone from skilled penetration testers, hostile state actors and organized criminals, to amateur cyber criminals.
The tools in this Activity Alert have been used to compromise information across a wide range of critical sectors, including health, finance, government, and defense. Their widespread availability presents a challenge for network defense and threat-actor attribution.
Experience from all our countries makes it clear that, while cyber threat actors continue to develop their capabilities, they still make use of established tools and techniques. Even the most sophisticated threat actor groups use common, publicly available tools to achieve their objectives.
Whatever these objectives may be, initial compromises of victim systems are often established through exploitation of common security weaknesses. Abuse of unpatched software vulnerabilities or poorly configured systems are common ways for a threat actor to gain access. The tools detailed in this Activity Alert come into play once a compromise has been achieved, enabling attackers to further their objectives within the victim’s systems.How to Use This Report

The tools detailed in this Activity Alert fall into five categories: Remote Access Trojans (RATs), webshells, credential stealers, lateral movement frameworks, and command and control (C2) obfuscators.
This Activity Alert provides an overview of the threat posed by each tool, along with insight into where and when it has been deployed by threat actors. Measures to aid detection and limit the effectiveness of each tool are also described.
The Activity Alert concludes with general advice for improving network defense practices.Technical Details

Remote Access Trojan: JBiFrost

First observed in May 2015, the JBiFrost RAT is a variant of the Adwind RAT, with roots stretching back to the Frutas RAT from 2012.
A RAT is a program that, once installed on a victim’s machine, allows remote administrative control. In a malicious context, it can—among many other functions—be used to install backdoors and key loggers, take screen shots, and exfiltrate data.
Malicious RATs can be difficult to detect because they are normally designed not to appear in lists of running programs and can mimic the behavior of legitimate applications.
To prevent forensic analysis, RATs have been known to disable security measures (e.g., Task Manager) and network analysis tools (e.g., Wireshark) on the victim’s system.In Use

JBiFrost RAT is typically employed by cyber criminals and low-skilled threat actors, but its capabilities could easily be adapted for use by state-sponsored threat actors.
Other RATs are widely used by Advanced Persistent Threat (APT) actor groups, such as Adwind RAT, against the aerospace and defense sector; or Quasar RAT, by APT10, against a broad range of sectors.
Threat actors have repeatedly compromised servers in our countries with the purpose of delivering malicious RATs to victims, either to gain remote access for further exploitation, or to steal valuable information such as banking credentials, intellectual property, or PII.Capabilities

JBiFrost RAT is Java-based, cross-platform, and multifunctional. It poses a threat to several different operating systems, including Windows, Linux, MAC OS X, and Android.
JBiFrost RAT allows threat actors to pivot and move laterally across a network or install additional malicious software. It is primarily delivered through emails as an attachment, usually an invoice notice, request for quotation, remittance notice, shipment notification, payment notice, or with a link to a file hosting service.
Past infections have exfiltrated intellectual property, banking credentials, and personally identifiable information (PII). Machines infected with JBiFrost RAT can also be used in botnets to carry out distributed denial-of-service attacks.Examples

Since early 2018, we have observed an increase in JBiFrost RAT being used in targeted attacks against critical national infrastructure owners and their supply chain operators. There has also been an increase in the RAT’s hosting on infrastructure located in our countries.
In early 2017, Adwind RAT was deployed via spoofed emails designed to look as if they originated from Society for Worldwide Interbank Financial Telecommunication, or SWIFT, network services.
Many other publicly available RATs, including variations of Gh0st RAT, have also been observed in use against a range of victims worldwide.Detection and Protection

Some possible indications of a JBiFrost RAT infection can include, but are not limited to:

Inability to restart the computer in safe mode,

Inability to open the Windows Registry Editor or Task Manager,

Significant increase in disk activity and/or network traffic,

Connection attempts to known malicious Internet Protocol (IP) addresses, and

Creation of new files and directories with obfuscated or random names.

Protection is best afforded by ensuring systems and installed applications are all fully patched and updated. The use of a modern antivirus program with automatic definition updates and regular system scans will also help ensure that most of the latest variants are stopped in their tracks. You should ensure that your organization is able to collect antivirus detections centrally across its estate and investigate RAT detections efficiently.
Strict application whitelisting is recommended to prevent infections from occurring.
The initial infection mechanism for RATs, including JBiFrost RAT, can be via phishing emails. You can help prevent JBiFrost RAT infections by stopping these phishing emails from reaching your users, helping users to identify and report phishing emails, and implementing security controls so that the malicious email does not compromise your device. The United Kingdom National Cyber Security Centre (UK NCSC) has published phishing guidance.Webshell: China Chopper

China Chopper is a publicly available, well-documented webshell that has been in widespread use since 2012.
Webshells are malicious scripts that are uploaded to a target host after an initial compromise and grant a threat actor remote administrative capability.
Once this access is established, webshells can also be used to pivot to additional hosts within a network.In Use

China Chopper is extensively used by threat actors to remotely access compromised web servers, where it provides file and directory management, along with access to a virtual terminal on the compromised device.
As China Chopper is just 4 KB in size and has an easily modifiable payload, detection and mitigation are difficult for network defenders.Capabilities

China Chopper has two main components: the China Chopper client-side, which is run by the attacker, and the China Chopper server, which is installed on the victim web server but is also attacker-controlled.
The webshell client can issue terminal commands and manage files on the victim server. Its MD5 hash is publicly available (originally posted on hxxp://www.maicaidao.com).
The MD5 hash of the web client is shown in table 1 below.Table 1: China Chopper webshell client MD5 hash

Webshell Client

MD5 Hash

caidao.exe

5001ef50c7e869253a7c152a638eab8a

The webshell server is uploaded in plain text and can easily be changed by the attacker. This makes it harder to define a specific hash that can identify adversary activity. In summer 2018, threat actors were observed targeting public-facing web servers that were vulnerable to CVE-2017-3066. The activity was related to a vulnerability in the web application development platform Adobe ColdFusion, which enabled remote code execution.
China Chopper was intended as the second-stage payload, delivered once servers had been compromised, allowing the threat actor remote access to the victim host. After successful exploitation of a vulnerability on the victim machine, the text-based China Chopper is placed on the victim web server. Once uploaded, the webshell server can be accessed by the threat actor at any time using the client application. Once successfully connected, the threat actor proceeds to manipulate files and data on the web server.
China Chopper’s capabilities include uploading and downloading files to and from the victim using the file-retrieval tool wget to download files from the internet to the target; and editing, deleting, copying, renaming, and even changing the timestamp, of existing files.Detection and protection

The most powerful defense against a webshell is to avoid the web server being compromised in the first place. Ensure that all the software running on public-facing web servers is up-to-date with security patches applied. Audit custom applications for common web vulnerabilities.[6]
One attribute of China Chopper is that every action generates a hypertext transfer protocol (HTTP) POST. This can be noisy and is easily spotted if investigated by a network defender.
While the China Chopper webshell server upload is plain text, commands issued by the client are Base64 encoded, although this is easily decodable.
The adoption of Transport Layer Security (TLS) by web servers has resulted in web server traffic becoming encrypted, making detection of China Chopper activity using network-based tools more challenging.
The most effective way to detect and mitigate China Chopper is on the host itself—specifically on public-facing web servers. There are simple ways to search for the presence of the web-shell using the command line on both Linux and Windows based operating systems.[7]
To detect webshells more broadly, network defenders should focus on spotting either suspicious process execution on web servers (e.g., Hypertext Preprocessor [PHP] binaries spawning processes) and out-of-pattern outbound network connections from web servers. Typically, web servers make predictable connections to an internal network. Changes in those patterns may indicate the presence of a web shell. You can manage network permissions to prevent web-server processes from writing to directories where PHP can be executed, or from modifying existing files.
We also recommend that you use web access logs as a source of monitoring, such as through traffic analytics. Unexpected pages or changes in traffic patterns can be early indicators.Credential Stealer: Mimikatz

Developed in 2007, Mimikatz is mainly used by attackers to collect the credentials of other users, who are logged into a targeted Windows machine. It does this by accessing the credentials in memory within a Windows process called Local Security Authority Subsystem Service (LSASS).
These credentials, either in plain text, or in hashed form, can be reused to give access to other machines on a network.
Although it was not originally intended as a hacking tool, in recent years Mimikatz has been used by multiple actors for malicious purposes. Its use in compromises around the world has prompted organizations globally to re-evaluate their network defenses.
Mimikatz is typically used by threat actors once access has been gained to a host and the threat actor wishes to move throughout the internal network. Its use can significantly undermine poorly configured network security.In Use

Mimikatz source code is publicly available, which means anyone can compile their own versions of the new tool and potentially develop new Mimikatz custom plug-ins and additional functionality.
Our cyber authorities have observed widespread use of Mimikatz among threat actors, including organized crime and state-sponsored groups.
Once a threat actor has gained local administrator privileges on a host, Mimikatz provides the ability to obtain the hashes and clear-text credentials of other users, enabling the threat actor to escalate privileges within a domain and perform many other post-exploitation and lateral movement tasks.
For this reason, Mimikatz has been bundled into other penetration testing and exploitation suites, such as PowerShell Empire and Metasploit.Capabilities

Mimikatz is best known for its ability to retrieve clear text credentials and hashes from memory, but its full suite of capabilities is extensive.
The tool can obtain Local Area Network Manager and NT LAN Manager hashes, certificates, and long-term keys on Windows XP (2003) through Windows 8.1 (2012r2). In addition, it can perform pass-the-hash or pass-the-ticket tasks and build Kerberos “golden tickets.”
Many features of Mimikatz can be automated with scripts, such as PowerShell, allowing a threat actor to rapidly exploit and traverse a compromised network. Furthermore, when operating in memory through the freely available “Invoke-Mimikatz” PowerShell script, Mimikatz activity is very difficult to isolate and identify.Examples

Mimikatz has been used across multiple incidents by a broad range of threat actors for several years. In 2011, it was used by unknown threat actors to obtain administrator credentials from the Dutch certificate authority, DigiNotar. The rapid loss of trust in DigiNotar led to the company filing for bankruptcy within a month of this compromise.
More recently, Mimikatz was used in conjunction with other malicious tools—in the NotPetya and BadRabbit ransomware attacks in 2017 to extract administrator credentials held on thousands of computers. These credentials were used to facilitate lateral movement and enabled the ransomware to propagate throughout networks, encrypting the hard drives of numerous systems where these credentials were valid.
In addition, a Microsoft research team identified use of Mimikatz during a sophisticated cyberattack targeting several high-profile technology and financial organizations. In combination with several other tools and exploited vulnerabilities, Mimikatz was used to dump and likely reuse system hashes.Detection and Protection

Updating Windows will help reduce the information available to a threat actor from the Mimikatz tool, as Microsoft seeks to improve the protection offered in each new Windows version.
To prevent Mimikatz credential retrieval, network defenders should disable the storage of clear text passwords in LSASS memory. This is default behavior for Windows 8.1/Server 2012 R2 and later, but can be specified on older systems which have the relevant security patches installed.[8] Windows 10 and Windows Server 2016 systems can be protected by using newer security features, such as Credential Guard.
Credential Guard will be enabled by default if:

You should verify that your physical and virtualized servers meet Microsoft’s minimum requirements for each release of Windows 10 and Windows Server.
Password reuse across accounts, particularly administrator accounts, makes pass-the-hash attacks far simpler. You should set user policies within your organization that discourage password reuse, even across common level accounts on a network. The freely available Local Administrator Password Solution from Microsoft can allow easy management of local administrator passwords, preventing the need to set and store passwords manually.
Network administrators should monitor and respond to unusual or unauthorized account creation or authentication to prevent Kerberos ticket exploitation, or network persistence and lateral movement. For Windows, tools such as Microsoft Advanced Threat Analytics and Azure Advanced Threat Protection can help with this.
Network administrators should ensure that systems are patched and up-to-date. Numerous Mimikatz features are mitigated or significantly restricted by the latest system versions and updates. But no update is a perfect fix, as Mimikatz is continually evolving and new third-party modules are often developed.
Most up-to-date antivirus tools will detect and isolate non-customized Mimikatz use and should therefore be used to detect these instances. But threat actors can sometimes circumvent antivirus systems by running Mimikatz in memory, or by slightly modifying the original code of the tool. Wherever Mimikatz is detected, you should perform a rigorous investigation, as it almost certainly indicates a threat actor is actively present in the network, rather than an automated process at work.
Several of Mimikatz’s features rely on exploitation of administrator accounts. Therefore, you should ensure that administrator accounts are issued on an as-required basis only. Where administrative access is required, you should apply privileged access management principles.
Since Mimikatz can only capture the accounts of those users logged into a compromised machine, privileged users (e.g., domain administrators) should avoid logging into machines with their privileged credentials. Detailed information on securing Active Directory is available from Microsoft.[9]
Network defenders should audit the use of scripts, particularly PowerShell, and inspect logs to identify anomalies. This will aid in identifying Mimikatz or pass-the-hash abuse, as well as in providing some mitigation against attempts to bypass detection software.Lateral Movement Framework: PowerShell Empire

PowerShell Empire is an example of a post-exploitation or lateral movement tool. It is designed to allow an attacker (or penetration tester) to move around a network after gaining initial access. Other examples of these tools include Cobalt Strike and Metasploit. PowerShell Empire can also be used to generate malicious documents and executables for social engineering access to networks.
The PowerShell Empire framework was designed as a legitimate penetration testing tool in 2015. PowerShell Empire acts as a framework for continued exploitation once a threat actor has gained access to a system.
The tool provides a threat actor with the ability to escalate privileges, harvest credentials, exfiltrate information, and move laterally across a network. These capabilities make it a powerful exploitation tool. Because it is built on a common legitimate application (PowerShell) and can operate almost entirely in memory, PowerShell Empire can be difficult to detect on a network using traditional antivirus tools.In Use

PowerShell Empire has become increasingly popular among hostile state actors and organized criminals. In recent years we have seen it used in cyber incidents globally across a wide range of sectors.
Initial exploitation methods vary between compromises, and threat actors can configure the PowerShell Empire uniquely for each scenario and target. This, in combination with the wide range of skill and intent within the PowerShell Empire user community, means that the ease of detection will vary. Nonetheless, having a greater understanding and awareness of this tool is a step forward in defending against its use by threat actors.Capabilities

PowerShell Empire enables a threat actor to carry out a range of actions on a victim’s machine and implements the ability to run PowerShell scripts without needing powershell.exe to be present on the system Its communications are encrypted and its architecture is flexible.
PowerShell Empire uses "modules" to perform more specific malicious actions. These modules provide the threat actor with a customizable range of options to pursue their goals on the victim’s systems. These goals include escalation of privileges, credential harvesting, host enumeration, keylogging, and the ability to move laterally across a network.
PowerShell Empire’s ease of use, flexible configuration, and ability to evade detection make it a popular choice for threat actors of varying abilities.Examples

During an incident in February 2018, a UK energy sector company was compromised by an unknown threat actor. This compromise was detected through PowerShell Empire beaconing activity using the tool’s default profile settings. Weak credentials on one of the victim’s administrator accounts are believed to have provided the threat actor with initial access to the network.
In early 2018, an unknown threat actor used Winter Olympics-themed socially engineered emails and malicious attachments in a spear-phishing campaign targeting several South Korean organizations. This attack had an additional layer of sophistication, making use of Invoke-PSImage, a stenographic tool that will encode any PowerShell script into an image.
In December 2017, APT19 targeted a multinational law firm with a phishing campaign. APT19 used obfuscated PowerShell macros embedded within Microsoft Word documents generated by PowerShell Empire.
Our cybersecurity authorities are also aware of PowerShell Empire being used to target academia. In one reported instance, a threat actor attempted to use PowerShell Empire to gain persistence using a Windows Management Instrumentation event consumer. However, in this instance, the PowerShell Empire agent was unsuccessful in establishing network connections due to the HTTP connections being blocked by a local security appliance.Detection and Protection

Identifying malicious PowerShell activity can be difficult due to the prevalence of legitimate PowerShell activity on hosts and the increased use of PowerShell in maintaining a corporate environment.
To identify potentially malicious scripts, PowerShell activity should be comprehensively logged. This should include script block logging and PowerShell transcripts.
Older versions of PowerShell should be removed from environments to ensure that they cannot be used to circumvent additional logging and controls added in more recent versions of PowerShell. This page provides a good summary of PowerShell security practices.[10]
The code integrity features in recent versions of Windows can be used to limit the functionality of PowerShell, preventing or hampering malicious PowerShell in the event of a successful intrusion.
A combination of script code signing, application whitelisting, and constrained language mode will prevent or limit the effect of malicious PowerShell in the event of a successful intrusion. These controls will also impact legitimate PowerShell scripts and it is strongly advised that they be thoroughly tested before deployment.
When organizations profile their PowerShell usage, they often find it is only used legitimately by a small number of technical staff. Establishing the extent of this legitimate activity will make it easier to monitor and investigate suspicious or unexpected PowerShell usage elsewhere on the network.C2 Obfuscation and Exfiltration: HUC Packet Transmitter

Attackers will often want to disguise their location when compromising a target. To do this, they may use generic privacy tools (e.g., Tor) or more specific tools to obfuscate their location.
HUC Packet Transmitter (HTran) is a proxy tool used to intercept and redirect Transmission Control Protocol (TCP) connections from the local host to a remote host. This makes it possible to obfuscate an attacker’s communications with victim networks. The tool has been freely available on the internet since at least 2009.
HTran facilitates TCP connections between the victim and a hop point controlled by a threat actor. Malicious threat actors can use this technique to redirect their packets through multiple compromised hosts running HTran to gain greater access to hosts in a network.In Use

The use of HTran has been regularly observed in compromises of both government and industry targets.
A broad range of threat actors have been observed using HTran and other connection proxy tools to

Evade intrusion and detection systems on a network,

Blend in with common traffic or leverage domain trust relationships to bypass security controls,

HTran can run in several modes, each of which forwards traffic across a network by bridging two TCP sockets. They differ in terms of where the TCP sockets are initiated from, either locally or remotely. The three modes are

Server (listen) – Both TCP sockets initiated remotely;

Client (slave) – Both TCP sockets initiated locally; and

Proxy (tran) – One TCP socket initiated remotely, the other initiated locally, upon receipt of traffic from the first connection.

HTran can inject itself into running processes and install a rootkit to hide network connections from the host operating system. Using these features also creates Windows registry entries to ensure that HTran maintains persistent access to the victim network.Examples

Recent investigations by our cybersecurity authorities have identified the use of HTran to maintain and obfuscate remote access to targeted environments.
In one incident, the threat actor compromised externally-facing web servers running outdated and vulnerable web applications. This access enabled the upload of webshells, which were then used to deploy other tools, including HTran.
HTran was installed into the ProgramData directory and other deployed tools were used to reconfigure the server to accept Remote Desktop Protocol (RDP) communications.
The threat actor issued a command to start HTran as a client, initiating a connection to a server located on the internet over port 80, which forwards RDP traffic from the local interface.
In this case, HTTP was chosen to blend in with other traffic that was expected to be seen originating from a web server to the internet. Other well-known ports used included:

Port 53 – Domain Name System

Port 443 - HTTP over TLS/Secure Sockets Layer

Port 3306 - MySQL

By using HTran in this way, the threat actor was able to use RDP for several months without being detected.

Detection and Protection

Attackers need access to a machine to install and run HTran, so network defenders should apply security patches and use good access control to prevent attackers from installing malicious applications.Network monitoring and firewalls can help prevent and detect unauthorized connections from tools such as HTran.
In some of the samples analyzed, the rootkit component of HTran only hides connection details when the proxy mode is used. When client mode is used, defenders can view details about the TCP connections being made.
HTran also includes a debugging condition that is useful for network defenders. In the event that a destination becomes unavailable, HTran generates an error message using the following format:
sprint(buffer, “[SERVER]connection to %s:%d error\r\n”, host, port2);
This error message is relayed to the connecting client in the clear. Network defenders can monitor for this error message to potentially detect HTran instances active in their environments.

Mitigations

There are several measures that will improve the overall cybersecurity of your organization and help protect it against the types of tools highlighted in this report. Network defenders are advised to seek further information using the links below.

Update your systems and software. Ensure your operating system and productivity applications are up to date. Users with Microsoft Office 365 licensing can use “click to run” to keep their office applications seamlessly updated.

Use modern systems and software. These have better security built-in. If you cannot move off out-of-date platforms and applications straight away, there are short-term steps you can take to improve your position.
See UK NCSC Guidance: https://www.ncsc.gov.uk/guidance/obs...urity-guidance.

Layer organization-wide phishing defenses. Detect and quarantine as many malicious email attachments and spam as possible, before they reach your end users. Multiple layers of defense will greatly cut the chances of a compromise.

NCCIC encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on the NCCIC/US-CERT homepage at http://www.us-cert.gov/.Feedback

NCCIC strives to make this report a valuable tool for our partners and welcomes feedback on how this publication could be improved. You can help by answering a few short questions about this report at the following URL: https://www.us-cert.gov/forms/feedback.References

The National Cybersecurity and Communications Integration Center (NCCIC) is aware of ongoing APT actor activity attempting to infiltrate the networks of global managed service providers (MSPs). Since May 2016, APT actors have used various tactics, techniques, and procedures (TTPs) for the purposes of cyber espionage and intellectual property theft. APT actors have targeted victims in several U.S. critical infrastructure sectors, including Information Technology (IT), Energy, Healthcare and Public Health, Communications, and Critical Manufacturing.
This Technical Alert (TA) provides information and guidance to assist MSP customer network and system administrators with the detection of malicious activity on their networks and systems and the mitigation of associated risks. This TA includes an overview of TTPs used by APT actors in MSP network environments, recommended mitigation techniques, and information on reporting incidents.Description

MSPs provide remote management of customer IT and end-user systems. The number of organizations using MSPs has grown significantly over recent years because MSPs allow their customers to scale and support their network environments at a lower cost than financing these resources internally. MSPs generally have direct and unfettered access to their customers’ networks, and may store customer data on their own internal infrastructure. By servicing a large number of customers, MSPs can achieve significant economies of scale. However, a compromise in one part of an MSP’s network can spread globally, affecting other customers and introducing risk.
Using an MSP significantly increases an organization’s virtual enterprise infrastructure footprint and its number of privileged accounts, creating a larger attack surface for cyber criminals and nation-state actors. By using compromised legitimate MSP credentials (e.g., administration, domain, user), APT actors can move bidirectionally between an MSP and its customers’ shared networks. Bidirectional movement between networks allows APT actors to easily obfuscate detection measures and maintain a presence on victims’ networks.Note: NCCIC previously released information related to this activity in Alert TA17-117A: Intrusions Affecting Multiple Victims Across Multiple Sectors published on April 27, 2017, which includes indicators of compromise, signatures, suggested detection methods, and recommended mitigation techniques.Technical Details

APT

APT actors use a range of “living off the land” techniques to maintain anonymity while conducting their attacks. These techniques include using legitimate credentials and trusted off-the-shelf applications and pre-installed system tools present in MSP customer networks.
Pre-installed system tools, such as command line scripts, are very common and used by system administrators for legitimate processes. Command line scripts are used to discover accounts and remote systems.
PowerSploit is a repository of Microsoft PowerShell and Visual Basic scripts and uses system commands such as netsh. PowerSploit, originally developed as a legitimate penetration testing tool, is widely misused by APT actors. These scripts often cannot be blocked because they are legitimate tools, so APT actors can use them and remain undetected on victim networks. Although network defenders can generate log files, APT actors’ use of legitimate scripts makes it difficult to identify system anomalies and other malicious activity.
When APT actors use system tools and common cloud services, it can also be difficult for network defenders to detect data exfiltration. APT actors have been observed using Robocopy—a Microsoft command line tool—to transfer exfiltrated and archived data from MSP client networks back through MSP network environments. Additionally, APT actors have been observed using legitimate PuTTY Secure Copy Client functions, allowing them to transfer stolen data securely and directly to third-party systems.Impact

A successful network intrusion can have severe impacts to the affected organization, particularly if the compromise becomes public. Possible impacts include

Temporary or permanent loss of sensitive or proprietary information,

Disruption to regular operations,

Financial losses to restore systems and files, and

Potential harm to the organization’s reputation.

Solution

Detection

Organizations should configure system logs to detect incidents and to identify the type and scope of malicious activity. Properly configured logs enable rapid containment and appropriate response.Response

An organization’s ability to rapidly respond to and recover from an incident begins with the development of an incident response capability. An organization’s response capability should focus on being prepared to handle the most common attack vectors (e.g., spearphishing, malicious web content, credential theft). In general, organizations should prepare by

Establishing and periodically updating an incident response plan.

Establishing written guidelines that prioritize incidents based on mission impact, so that an appropriate response can be initiated.

Developing procedures and out-of-band lines of communication to handle incident reporting for internal and external relationships.

Exercising incident response measures for various intrusion scenarios regularly, as part of a training regime.

Committing to an effort that secures the endpoint and network infrastructure: prevention is less costly and more effective than reacting after an incident.

Mitigation

Manage Supply Chain Risk

MSP clients that do not conduct the majority of their own network defense should work with their MSP to determine what they can expect in terms of security. MSP clients should understand the supply chain risk associated with their MSP. Organizations should manage risk equally across their security, legal, and procurement groups. MSP clients should also refer to cloud security guidance from the National Institute of Standards and Technology to learn about MSP terms of service, architecture, security controls, and risks associated with cloud computing and data protection.[1][2][3]Architecture

Restricting access to networks and systems is critical to containing an APT actor’s movement. Provided below are key items that organizations should implement and periodically audit to ensure their network environment’s physical and logical architecture limits an APT actor’s visibility and access.Virtual Private Network Connection Recommendations

Use a dedicated Virtual Private Network (VPN) for MSP connection. The organization’s local network should connect to the MSP via a dedicated VPN. The VPN should use certificate-based authentication and be hosted on its own device.

Terminate VPN within a demilitarized zone (DMZ). The VPN should terminate within a DMZ that is isolated from the internal network. Physical systems used within the DMZ should not be used on or for the internal network.

Restrict VPN traffic to and from MSP. Access to and from the VPN should be confined to only those networks and protocols needed for service. All other internal networks and protocols should be blocked. At a minimum, all failed attempts should be logged.

Update VPN authentication certificates annually. Update the certificates used to establish the VPN connection no less than annually. Consider rotating VPN authentication certificates every six months.

Ensure VPN connections are logged, centrally managed, and reviewed. All VPN connection attempts should be logged in a central location. Investigate connections using dedicated certificates to confirm they are legitimate.

Network Architecture Recommendations

Ensure internet-facing networks reside on separate physical systems. All internet-accessible network zones (e.g., perimeter network, DMZ) should reside on their own physical systems, including the security devices used to protect the network environment.

Separate internal networks by function, location, and risk profile. Internal networks should be segmented by function, location, and/or enterprise workgroup. All communication between networks should use Access Control Lists and security groups to implement restrictions.

Use firewalls to protect server(s) and designated high-risk networks. Firewalls should reside at the perimeter of high-risk networks, including those hosting servers. Access to these networks should be properly restricted. Organizations should enable logging, using a centrally managed logging system.

Configure and enable private Virtual Local Area Networks (VLANs). Enable private VLANs and group them according to system function or user workgroup.

Implement host firewalls. In addition to the physical firewalls in place at network boundaries, hosts should also be equipped and configured with host-level firewalls to restrict communications from other workstations (this decreases workstation-to-workstation communication).

Ensure internal and external Domain Name System (DNS) queries are performed by dedicated servers. All systems should leverage dedicated internal DNS servers for their queries. Ensure that DNS queries for external hosts using User Datagram Protocol (UDP)/53 are permitted for only these hosts and are filtered through a DNS reputation service, and that outbound UDP/53 network traffic by all other systems is denied. Ensure that TCP/53 is not permitted by any system within the network environment. All attempts to use TCP/53 and UDP/53 should be centrally logged and investigated.

Restrict access to unauthorized public file shares. Access to public file shares that are not used by the organization—such as Dropbox, Google Drive, and OneDrive—should be denied. Attempts to access public file share sites should be centrally logged and investigated. Recommended additional action: monitor all egress traffic for possible exfiltration of data.

Disable or block all network services that are not required at network boundary. Only those services needed to operate should be enabled and/or authorized at network boundaries. These services are typically limited to TCP/137, TCP/139, and TCP/445. Additional services may be needed, depending on the network environment, these should be tightly controlled to only send and receive from certain whitelisted Internet Protocol addresses, if possible.

Authentication, Authorization, and Accounting

Compromised account credentials continue to be the number one way threat actors are able to penetrate a network environment. The accounts organizations create for MSPs increase the risk of credential compromise, as MSP accounts typically require elevated access. It is important organizations’ adhere to best practices for password and permission management, as this can severely limit a threat actor’s ability to access and move laterally across a network. Provided below are key items organizations should implement and routinely audit to ensure these risks are mitigated.Account Configuration Recommendations

Ensure MSP accounts are not assigned to administrator groups. MSP accounts should not be assigned to the Enterprise Administrator (EA) or Domain Administrator (DA) groups.

Restrict MSP accounts to only the systems they manage. Place systems in security groups and only grant MSP account access as required. Administrator access to these systems should be avoided when possible.

Use service accounts for MSP agents and services. If an MSP requires the installation of an agent or other local service, create service accounts for this purpose. Disable interactive logon for these accounts.

Restrict MSP accounts by time and/or date. Set expiration dates reflecting the end of the contract on accounts used by MSPs when those accounts are created or renewed. Additionally, if MSP services are only required during business hours, time restrictions should also be enabled and set accordingly. Consider keeping MSP accounts disabled until they are needed and disabling them once the work is completed.

Use a network architecture that includes account tiering. By using an account tiering structure, higher privileged accounts will never have access or be found on lower privileged layers of the network. This keeps EA and DA level accounts on the higher, more protected tiers of the network. Ensure that EA and DA accounts are removed from local administrator groups on workstations.

Logging Configuration Recommendations

Enable logging on all network systems and devices and send logs to a central location. All network systems and devices should have their logging features enabled. Logs should be stored both locally and centrally to ensure they are preserved in the event of a network failure. Logs should also be backed up regularly and stored in a safe location.

Ensure central log servers reside in an enclave separate from other servers and workstations. Log servers should be isolated from the internet and network environment to further protect them from compromise. The firewall at the internal network boundary should only permit necessary services (e.g., UDP/514).

Configure local logs to store no less than seven days of log data. The default threshold for local logging is typically three days or a certain file size (e.g., 5 MB). Configure local logs to store no less than seven days of log data. Seven days of logs will cover the additional time in which problems may not be identified, such as holidays. In the event that only size thresholds are available, NCCIC recommends that this parameter be set to a large value (e.g., 512MB to1024MB) to ensure that events requiring a high amount of log data, such as brute force attacks, can be adequately captured.

Configure central logs to store no less than one year of log data. Central log servers should store no less than a year’s worth of data prior to being rolled off. Consider increasing this capacity to two years, if possible.

Install and properly configure a Security Information and Event Management (SIEM) appliance. Install a SIEM appliance within the log server enclave. Configure the SIEM appliance to alert on anomalous activity identified by specific events and on significant derivations from baselined activity.

Enable PowerShell logging. Organizations that use Microsoft PowerShell should ensure it is upgraded the latest version (minimum version 5) to use the added security of advanced logging and to ensure these logs are being captured and analyzed. PowerShell’s features include advanced logging, interaction with application whitelisting (if using Microsoft’s AppLocker), constrained language mode, and advanced malicious detection with Antimalware Scan Interface. These features will help protect an organization’s network by limiting what scripts can be run, logging all executed commands, and scanning all scripts for known malicious behaviors.

Establish and implement a log review process. Logs that go unanalyzed are useless. It is critical to network defense that organizations establish a regular cycle for reviewing logs and developing analytics to identify patterns.

Operational Controls

Building a sound architecture supported by strong technical controls is only the first part to protecting a network environment. It is just as critical that organizations continuously monitor their systems, update configurations to reflect changes in their network environment, and maintain relationships with MSPs. Listed below are key operational controls organizations should incorporate for protection from threats.Operational Control Recommendations

Create a baseline for system and network behavior. System, network, and account behavior should be baselined to make it easier to track anomalies within the collected logs. Without this baseline, network administrators will not be able to identify the “normal” behaviors for systems, network traffic, and accounts.

Review network device configurations every six months. No less than every six months, review the active configurations of network devices for unauthorized settings (consider reviewing more frequently). Baseline configurations and their checksums should be stored in a secure location and be used to validate files.

Review network environment Group Policy Objects (GPOs) every six months. No less than every six months, review GPOs for unauthorized settings (consider reviewing more frequently). Baseline configurations and their checksums should be stored in a secure location and be used to validate files.

Continuously monitor and investigate SIEM appliance alerts. The SIEM appliance should be continuously monitored for alerts. All events should be investigated and documented for future reference.

Periodically review SIEM alert thresholds. Review SIEM appliance alert thresholds no less than every three months. Thresholds should be updated to reflect changes, such as new systems, activity variations, and new or old services being used within the network environment.

Disable or remove inactive accounts. Periodically monitor accounts for activity and disable or remove accounts that have not been active within a certain period, not to exceed 30 days. Consider including account management into the employee onboarding and offboarding processes.

Regularly update software and operating systems. Ensuring that operating systems and software is up-to-date is critical for taking advantage of a vendor’s latest security offerings. These offerings can include mitigating known vulnerabilities and offering new protections (e.g., credential protections, increased logging, forcing signed software).

It is important to note that—while the recommendations provided in this TA aim at preventing the initial attack vectors and the spread of any malicious activity—there is no single solution to protecting and defending a network. NCCIC recommends network defenders use a defense-in-depth strategy to increase the odds of successfully identifying an intrusion, stopping malware, and disrupting threat actor activity. The goal is to make it as difficult as possible for an attacker to be successful and to force them to use methods that are easier to detect with higher operational costs.Report Unauthorized Network Access

Contact DHS or your local FBI office immediately. To report an intrusion and request resources for incident response or technical assistance, contact NCCIC at (NCCICCustomerService@hq.dhs.gov or 888-282-0870), FBI through a local field office, or the FBI’s Cyber Division (CyWatch@fbi.gov or 855-292-3937).References

This technical alert addresses the exploitation of trusted network relationships and the subsequent illicit use of legitimate credentials by Advanced Persistent Threat (APT) actors. It identifies APT actors' tactics, techniques, and procedures (TTPs) and describes the best practices that could be employed to mitigate each of them. The mitigations for each TTP are arranged according to the National Institute of Standards and Technology (NIST) Cybersecurity Framework core functions of Protect, Detect, Respond, and Recover.Description

APT actors are using multiple mechanisms to acquire legitimate user credentials to exploit trusted network relationships in order to expand unauthorized access, maintain persistence, and exfiltrate data from targeted organizations. Suggested best practices for administrators to mitigate this threat include auditing credentials, remote-access logs, and controlling privileged access and remote access.Impact

APT actors are conducting malicious activity against organizations that have trusted network relationships with potential targets, such as a parent company, a connected partner, or a contracted managed service provider (MSP). APT actors can use legitimate credentials to expand unauthorized access, maintain persistence, exfiltrate data, and conduct other operations, while appearing to be authorized users. Leveraging legitimate credentials to exploit trusted network relationships also allows APT actors to access other devices and other trusted networks, which affords intrusions a high level of persistence and stealth.Solution

Recommended best practices for mitigating this threat include rigorous credential and privileged-access management, as well as remote-access control, and audits of legitimate remote-access logs. While these measures aim to prevent the initial attack vectors and the spread of malicious activity, there is no single proven threat response.
Using a defense-in-depth strategy is likely to increase the odds of successfully disrupting adversarial objectives long enough to allow network defenders to detect and respond before the successful completion of a threat actor’s objectives.
Any organization that uses an MSP to provide services should monitor the MSP's interactions within their organization’s enterprise networks, such as account use, privileges, and access to confidential or proprietary information. Organizations should also ensure that they have the ability to review their security and monitor their information hosted on MSP networks.APT TTPs and Corresponding Mitigations

The following table displays the TTPs employed by APT actors and pairs them with mitigations that network defenders can implement.Table 1: APT TTPs and Mitigations

Monitor accounts associated with a compromise for abnormal behaviors, including unusual connections to nonstandard resources or attempts to elevate privileges, enumerate, or execute unexpected programs or applications.

Prevent the execution of unauthorized software, such as PSCP and Robocopy.

Detect:

Monitor for use of archive and compression tools.

Monitor egress traffic for anomalous behaviors, such as irregular outbound connections, malformed or abnormally large packets, or bursts of data to detect beaconing and exfiltration.

Detailed Mitigation Guidance

Manage Credentials and Control Privileged Access

Compromising the credentials of legitimate users automatically provides a threat actor access to the network resources available to those users and helps that threat actor move more covertly through the network. Adopting and enforcing a strong-password policy can reduce a threat actor’s ability to compromise legitimate accounts; transitioning to multifactor authentication solutions increases the difficulty even further. Additionally, monitoring user account logins—whether failed or successful—and deploying tools and services to detect illicit use of credentials can help network defenders identify potentially malicious activity.
Threat actors regularly target privileged accounts because they not only grant increased access to high-value assets in the network, but also more easily enable lateral movement, and often provide mechanisms for the actors to hide their activities. Privileged access can be controlled by ensuring that only those users requiring elevated privileges are granted those accesses and, in accordance with the principle of least privilege, by restricting the use of those privileged accounts to instances where elevated privileges are required for specific tasks. It is also important to carefully manage and monitor local-administrator and MSP accounts because they inherently function with elevated privileges and are often ignored after initial configuration.
A key way to control privileged accounts is to segregate and control administrator (admin) privileges. All administrative credentials should be tightly controlled, restricted to a function, or even limited to a specific amount of time. For example, only dedicated workstation administrator accounts should be able to administer workstations. Server accounts, such as general, Structured Query Language, or email admins, should not have administrative access to workstations. The only place domain administrator (DA) or enterprise administrator (EA) credentials should ever be used is on a domain controller. Both EA and DA accounts should be removed from the local-administrators group on all other devices. On UNIX devices, sudo (or root) access should be tightly restricted in the same manner. Employing a multifactor authentication solution for admin accounts adds another layer of security and can significantly reduce the impact of a password compromise because the threat actor needs the other factor—that is, a smartcard or a token—for authentication.
Additionally, administrators should disable unencrypted remote-administrative protocols and services, which are often enabled by default. Protocols required for operations must be authorized, and the most secure version must be implemented. All other protocols must be disabled, particularly unencrypted remote-administrative protocols used to manage network infrastructure devices, such as Telnet, Hypertext Transfer Protocol, File Transfer Protocol, Trivial File Transfer Protocol, and Simple Network Management Protocol versions 1 and 2.Control Remote Access and Audit Remote Logins

Control legitimate remote access by trusted service providers. Similar to other administrative accounts, MSP accounts should be given the least privileges needed to operate. In addition, it is recommended that MSP accounts either be limited to work hours, when they can be monitored, or disabled until work needs to be done. MSP accounts should also be held to the same or higher levels of security for credential use, such as multifactor authentication or more complex passwords subject to shorter expiration timeframes.

Establish a baseline on the network. Network administrators should work with network owners or MSPs to establish what normal baseline behavior and traffic look like on the network. It is also advisable to discuss what accesses are needed when the network is not being actively managed. This will allow local network personnel to know what acceptable cross-network or MSP traffic looks like in terms of ports, protocols, and credential use.

Monitor system event logs for anomalous activity. Network logs should be captured to help detect and identify anomalous and potentially malicious activity. In addition to the application whitelisting logs, administrators should ensure that other critical event logs are being captured and stored, such as service installation, account usage, pass-the-hash detection, and RDP detection logs. Event logs can help identify the use of tools like Mimikatz and the anomalous use of legitimate credentials or hashes. Baselining is critical for effective event log analysis, especially in the cases of MSP account behavior.

Control Microsoft RDP. Adversaries with valid credentials can use RDP to move laterally and access information on other, more sensitive systems. These techniques can help protect against the malicious use of RDP:

Assess the need to have RDP enabled on systems and, if required, limit connections to specific, trusted hosts.

Verify that cloud environments adhere to best practices, as defined by the cloud service provider. After the cloud environment setup is complete, ensure that RDP ports are not enabled unless required for a business purpose.

Place any system with an open RDP port behind a firewall and require users to communicate via a VPN through a firewall.

Perform regular checks to ensure RDP port 3389 is not open to the public internet. Enforce strong-password and account-lockout policies to defend against brute force attacks.

Enable the restricted-administrator option available in Windows 8.1 and Server 2012 R2 to ensure that reusable credentials are neither sent in plaintext during authentication nor cached.

Restrict Secure Shell (SSH) trusts. It is important that SSH trusts be carefully managed and secured because improperly configured and overly permissive trusts can provide adversaries with initial access opportunities and the means for lateral movement within a network. Access lists should be configured to limit which users are able to log in via SSH, and root login via SSH should be disabled. Additionally, the system should be configured to only allow connections from specific workstations, preferably administrative workstations used only for the purpose of administering systems.

Report Unauthorized Network Access

Contact DHS or your local FBI office immediately. To report an intrusion and request resources for incident response or technical assistance, contact NCCIC at (NCCICCustomerService@hq.dhs.gov or 888-282-0870), FBI through a local field office, or the FBI’s Cyber Division (CyWatch@fbi.gov or 855-292-3937).References

This joint Technical Alert (TA) is the result of analytic efforts between the Department of Homeland Security (DHS), the Department of the Treasury (Treasury), and the Federal Bureau of Investigation (FBI). Working with U.S. government partners, DHS, Treasury, and FBI identified malware and other indicators of compromise (IOCs) used by the North Korean government in an Automated Teller Machine (ATM) cash-out scheme—referred to by the U.S. Government as “FASTCash.” The U.S. Government refers to malicious cyber activity by the North Korean government as HIDDEN COBRA. For more information on HIDDEN COBRA activity, visit https://www.us-cert.gov/hiddencobra.
FBI has high confidence that HIDDEN COBRA actors are using the IOCs listed in this report to maintain a presence on victims’ networks to enable network exploitation. DHS, FBI, and Treasury are distributing these IOCs to enable network defense and reduce exposure to North Korean government malicious cyber activity.
This TA also includes suggested response actions to the IOCs provided, recommended mitigation techniques, and information on reporting incidents. If users or administrators detect activity associated with the malware families associated with FASTCash, they should immediately flag it, report it to the DHS National Cybersecurity and Communications Integration Center (NCCIC) or the FBI Cyber Watch (CyWatch), and give it the highest priority for enhanced mitigation.
NCCIC conducted analysis on 10 malware samples related to this activity and produced a Malware Analysis Report (MAR). MAR-1021537 – HIDDEN COBRA FASTCash-Related Malware examines the tactics, techniques, and procedures observed in the malware. Visit the MAR-10201537 page for the report and associated IOCs.Description

Since at least late 2016, HIDDEN COBRA actors have used FASTCash tactics to target banks in Africa and Asia. At the time of this TA’s publication, the U.S. Government has not confirmed any FASTCash incidents affecting institutions within the United States.
FASTCash schemes remotely compromise payment switch application servers within banks to facilitate fraudulent transactions. The U.S. Government assesses that HIDDEN COBRA actors will continue to use FASTCash tactics to target retail payment systems vulnerable to remote exploitation.
According to a trusted partner’s estimation, HIDDEN COBRA actors have stolen tens of millions of dollars. In one incident in 2017, HIDDEN COBRA actors enabled cash to be simultaneously withdrawn from ATMs located in over 30 different countries. In another incident in 2018, HIDDEN COBRA actors enabled cash to be simultaneously withdrawn from ATMs in 23 different countries.
HIDDEN COBRA actors target the retail payment system infrastructure within banks to enable fraudulent ATM cash withdrawals across national borders. HIDDEN COBRA actors have configured and deployed legitimate scripts on compromised switch application servers in order to intercept and reply to financial request messages with fraudulent but legitimate-looking affirmative response messages. Although the infection vector is unknown, all of the compromised switch application servers were running unsupported IBM Advanced Interactive eXecutive (AIX) operating system versions beyond the end of their service pack support dates; there is no evidence HIDDEN COBRA actors successfully exploited the AIX operating system in these incidents.
HIDDEN COBRA actors exploited the targeted systems by using their knowledge of International Standards Organization (ISO) 8583—the standard for financial transaction messaging—and other tactics. HIDDEN COBRA actors most likely deployed ISO 8583 libraries on the targeted switch application servers. Malicious threat actors use these libraries to help interpret financial request messages and properly construct fraudulent financial response messages.

Figure 1: Anatomy of a FASTCash scheme

A review of log files showed HIDDEN COBRA actors making typos and actively correcting errors while configuring the targeted server for unauthorized activity. Based on analysis of the affected systems, analysts believe that the scripts —used by HIDDEN COBRA actors and explained in the Technical Details section below—inspected inbound financial request messages for specific primary account numbers (PANs). The scripts generated fraudulent financial response messages only for the request messages that matched the expected PANs. Most accounts used to initiate the transactions had minimal account activity or zero balances.
Analysts believe HIDDEN COBRA actors blocked transaction messages to stop denial messages from leaving the switch and used a GenerateResponse* function to approve the transactions. These response messages were likely sent for specific PANs matched using CheckPan()verification (see figure 1 for additional details on CheckPan()).Technical Details

HIDDEN COBRA actors used malicious Windows executable applications, command-line utility applications, and other files in the FASTCash campaign to perform transactions and interact with financial systems, including the switch application server. The initial infection vector used to compromise victim networks is unknown; however, analysts surmise HIDDEN COBRA actors used spear-phishing emails in targeted attacks against bank employees. HIDDEN COBRA actors likely used Windows-based malware to explore a bank’s network to identify the payment switch application server. Although these threat actors used different malware in each known incident, static analysis of malware samples indicates similarities in malware capabilities and functionalities.
HIDDEN COBRA actors likely used legitimate credentials to move laterally through a bank’s network and to illicitly access the switch application server. This pattern suggests compromised systems within a bank’s network were used to access and compromise the targeted payment switch application server.
Although some of the files used by HIDDEN COBRA actors were legitimate, and not inherently malicious, it is likely that HIDDEN COBRA actors used these legitimate files for malicious purposes. See MAR-1021537 for details on the files used. Malware samples obtained for analysis included AIX executable files intended for a proprietary UNIX operating system developed by IBM. The IBM AIX executable files were designed to conduct code injection and inject a library into a currently running process. One of the sample AIX executables obtained provides export functions, which allows an application to perform transactions on financial systems using the ISO 8583 standard.
Upon successful compromise of a bank’s payment switch application server, HIDDEN COBRA actors likely deployed legitimate scripts—using command-line utility applications on the payment switch application server—to enable fraudulent behavior by the system in response to what would otherwise be normal payment switch application server activity. Figure 1 depicts the pattern of fraudulent behavior. The scripts alter the expected behavior of the server by targeting the business process, rather than exploiting a technical process.
During analysis of log files associated with known FASTCash incidents, analysts identified the following commonalities:

Execution of .so (shared object) commands using the following pattern: /tmp/.ICE-unix/e
/tmp.ICE-unix/m.so

Execution of the script which contained a similar, but slightly different, command: ./sun
/tmp/.ICE-unix/engine.so

The file is named sun and runs out of the /tmp/.ICE-unix directory.

Additionally, both commands use either the inject (mode 0) or eject (mode 1) argument with the following ISO 8583 libraries:

m.so [with argument “0” or “1”]

m1.so [with argument “0” or “1”]

m2.so [with argument “0” or “1”]

m3.so [with argument “0” or “1”]

Detection and Response

NCCIC recommends administrators review bash history logs of all users with root privileges. Administrators can find commands entered by users in the bash history logs; these would indicate the execution of scripts on the switch application server. Administrators should log and monitor all commands.
The U.S. Government recommends that network administrators review MAR-10201537 for IOCs related to the HIDDEN COBRA FASTCash campaign, identify whether any of the provided IOCs fall within their organization’s network, and—if found—take necessary measures to remove the malware.Impact

A successful network intrusion can have severe impacts, particularly if the compromise becomes public. Possible impacts to the affected organization include

For additional information on malware incident prevention and handling, see the National Institute of Standards and Technology (NIST) Special Publication (SP) 800-83: Guide to Malware Incident Prevention and Handling for Desktops and Laptops.[1]Response to Unauthorized Network Access

Contact DHS or your local FBI office immediately. To report an intrusion and request resources for incident response or technical assistance, contact NCCIC at (NCCICCustomerService@hq.dhs.gov or 888-282-0870), FBI through a local field office, or the FBI’s Cyber Division (CyWatch@fbi.gov or 855-292-3937).References

Emotet is an advanced, modular banking Trojan that primarily functions as a downloader or dropper of other banking Trojans. Emotet continues to be among the most costly and destructive malware affecting state, local, tribal, and territorial (SLTT) governments, and the private and public sectors.
This joint Technical Alert (TA) is the result of Multi-State Information Sharing & Analysis Center (MS-ISAC) analytic efforts, in coordination with the Department of Homeland Security (DHS) National Cybersecurity and Communications Integration Center (NCCIC).Description

Emotet continues to be among the most costly and destructive malware affecting SLTT governments. Its worm-like features result in rapidly spreading network-wide infection, which are difficult to combat. Emotet infections have cost SLTT governments up to $1 million per incident to remediate.
Emotet is an advanced, modular banking Trojan that primarily functions as a downloader or dropper of other banking Trojans. Additionally, Emotet is a polymorphic banking Trojan that can evade typical signature-based detection. It has several methods for maintaining persistence, including auto-start registry keys and services. It uses modular Dynamic Link Libraries (DLLs) to continuously evolve and update its capabilities. Furthermore, Emotet is Virtual Machine-aware and can generate false indicators if run in a virtual environment.
Emotet is disseminated through malspam (emails containing malicious attachments or links) that uses branding familiar to the recipient; it has even been spread using the MS-ISAC name. As of July 2018, the most recent campaigns imitate PayPal receipts, shipping notifications, or “past-due” invoices purportedly from MS-ISAC. Initial infection occurs when a user opens or clicks the malicious download link, PDF, or macro-enabled Microsoft Word document included in the malspam. Once downloaded, Emotet establishes persistence and attempts to propagate the local networks through incorporated spreader modules.Figure 1: Malicious email distributing Emotet

NetPass.exe is a legitimate utility developed by NirSoft that recovers all network passwords stored on a system for the current logged-on user. This tool can also recover passwords stored in the credentials file of external drives.

Outlook scraper is a tool that scrapes names and email addresses from the victim’s Outlook accounts and uses that information to send out additional phishing emails from the compromised accounts.

WebBrowserPassView is a password recovery tool that captures passwords stored by Internet Explorer, Mozilla Firefox, Google Chrome, Safari, and Opera and passes them to the credential enumerator module.

Mail PassView is a password recovery tool that reveals passwords and account details for various email clients such as Microsoft Outlook, Windows Mail, Mozilla Thunderbird, Hotmail, Yahoo! Mail, and Gmail and passes them to the credential enumerator module.

Credential enumerator is a self-extracting RAR file containing two components: a bypass component and a service component. The bypass component is used for the enumeration of network resources and either finds writable share drives using Server Message Block (SMB) or tries to brute force user accounts, including the administrator account. Once an available system is found, Emotet writes the service component on the system, which writes Emotet onto the disk. Emotet’s access to SMB can result in the infection of entire domains (servers and clients).

Figure 2: Emotet infection process

To maintain persistence, Emotet injects code into explorer.exe and other running processes. It can also collect sensitive information, including system name, location, and operating system version, and connects to a remote command and control server (C2), usually through a generated 16-letter domain name that ends in “.eu.” Once Emotet establishes a connection with the C2, it reports a new infection, receives configuration data, downloads and runs files, receives instructions, and uploads data to the C2 server.
Emotet artifacts are typically found in arbitrary paths located off of the AppData\Local and AppData\Roaming directories. The artifacts usually mimic the names of known executables. Persistence is typically maintained through Scheduled Tasks or via registry keys. Additionally, Emotet creates randomly-named files in the system root directories that are run as Windows services. When executed, these services attempt to propagate the malware to adjacent systems via accessible administrative shares.Note: it is essential that privileged accounts are not used to log in to compromised systems during remediation as this may accelerate the spread of the malware.Example Filenames and Paths:
C:\Users\\AppData \Local\Microsoft\Windows\shedaudio.exe
C:\Users\\AppData\Roaming\Macromedia\Flash Player\macromedia\bin\flashplayer.exeTypical Registry Keys:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunSystem Root Directories:
C:\Windows\11987416.exe
C:\Windows\System32\46615275.exe
C:\Windows\System32\shedaudio.exe
C:\Windows\SysWOW64\f9jwqSbS.exe

Impact

Negative consequences of Emotet infection include

temporary or permanent loss of sensitive or proprietary information,

disruption to regular operations,

financial losses incurred to restore systems and files, and

potential harm to an organization’s reputation.

Solution

NCCIC and MS-ISAC recommend that organizations adhere to the following general best practices to limit the effect of Emotet and similar malspam:

Use Group Policy Object to set a Windows Firewall rule to restrict inbound SMB communication between client systems. If using an alternative host-based intrusion prevention system (HIPS), consider implementing custom modifications for the control of client-to-client SMB communication. At a minimum, create a Group Policy Object that restricts inbound SMB connections to clients originating from clients.

Use antivirus programs, with automatic updates of signatures and software, on clients and servers.

Implement filters at the email gateway to filter out emails with known malspam indicators, such as known malicious subject lines, and block suspicious IP addresses at the firewall.

If your organization does not have a policy regarding suspicious emails, consider creating one and specifying that all suspicious emails should be reported to the security or IT department.

Mark external emails with a banner denoting it is from an external source. This will assist users in detecting spoofed emails.

Provide employees training on social engineering and phishing. Urge employees not to open suspicious emails, click links contained in such emails, or post sensitive information online, and to never provide usernames, passwords, or personal information in answer to any unsolicited request. Educate users to hover over a link with their mouse to verify the destination prior to clicking on the link.

Consider blocking file attachments that are commonly associated with malware, such as .dll and .exe, and attachments that cannot be scanned by antivirus software, such as .zip files.

Adhere to the principal of least privilege, ensuring that users have the minimum level of access required to accomplish their duties. Limit administrative credentials to designated administrators.

If a user or organization believes they may be infected, NCCIC and MS-ISAC recommend running an antivirus scan on the system and taking action to isolate the infected workstation based on the results. If multiple workstations are infected, the following actions are recommended:

Identify, shutdown, and take the infected machines off the network;

Consider temporarily taking the network offline to perform identification, prevent reinfections, and stop the spread of the malware;

Do not log in to infected systems using domain or shared local administrator accounts;

Reimage the infected machine(s);

After reviewing systems for Emotet indicators, move clean systems to a containment virtual local area network that is segregated from the infected network;

Issue password resets for both domain and local credentials;

Because Emotet scrapes additional credentials, consider password resets for other applications that may have had stored credentials on the compromised machine(s);

Identify the infection source (patient zero); and

Review the log files and the Outlook mailbox rules associated with the infected user account to ensure further compromises have not occurred. It is possible that the Outlook account may now have rules to auto-forward all emails to an external email address, which could result in a data breach.

Reporting

MS-ISAC is the focal point for cyber threat prevention, protection, response, and recovery for the nation’s SLTT governments. More information about this topic, as well as 24/7 cybersecurity assistance for SLTT governments, is available by phone at 866-787-4722, by email at SOC@cisecurity.org, or on MS-ISAC’s website at https://msisac.cisecurity.org/.
To report an intrusion and request resources for incident response or technical assistance, contact NCCIC by email at NCCICCustomerService@hq.dhs.gov or by phone at 888-282-0870.References

This joint Technical Alert (TA) is the result of analytic efforts between the Department of Homeland Security (DHS) and the Federal Bureau of Investigation (FBI). Working with U.S. government partners, DHS and FBI identified Internet Protocol (IP) addresses and other indicators of compromise (IOCs) associated with two families of malware used by the North Korean government:

a remote access tool (RAT), commonly known as Joanap; and

a Server Message Block (SMB) worm, commonly known as Brambul.

The U.S. Government refers to malicious cyber activity by the North Korean government as HIDDEN COBRA. For more information on HIDDEN COBRA activity, visit https://www.us-cert.gov/hiddencobra.
FBI has high confidence that HIDDEN COBRA actors are using the IP addresses—listed in this report’s IOC files—to maintain a presence on victims’ networks and enable network exploitation. DHS and FBI are distributing these IP addresses and other IOCs to enable network defense and reduce exposure to any North Korean government malicious cyber activity.
This alert also includes suggested response actions to the IOCs provided, recommended mitigation techniques, and information on how to report incidents. If users or administrators detect activity associated with these malware families, they should immediately flag it, report it to the DHS National Cybersecurity and Communications Integration Center (NCCIC) or the FBI Cyber Watch (CyWatch), and give it the highest priority for enhanced mitigation.
See the following links for a downloadable copy of IOCs:

NCCIC conducted analysis on four malware samples and produced a Malware Analysis Report (MAR). MAR-10135536.3 – RAT/Worm examines the tactics, techniques, and procedures observed in the malware. Visit MAR-10135536.3 – HIDDEN COBRA RAT/Worm for the report and associated IOCs.Description

According to reporting of trusted third parties, HIDDEN COBRA actors have likely been using both Joanap and Brambul malware since at least 2009 to target multiple victims globally and in the United States—including the media, aerospace, financial, and critical infrastructure sectors. Users and administrators should review the information related to Joanap and Brambul from the Operation Blockbuster Destructive Malware Report [1] in conjunction with the IP addresses listed in the .csv and .stix files provided within this alert. Like many of the families of malware used by HIDDEN COBRA actors, Joanap, Brambul, and other previously reported custom malware tools, may be found on compromised network nodes. Each malware tool has different purposes and functionalities.
Joanap malware is a fully functional RAT that is able to receive multiple commands, which can be issued by HIDDEN COBRA actors remotely from a command and control server. Joanap typically infects a system as a file dropped by other HIDDEN COBRA malware, which users unknowingly downloaded either when they visit sites compromised by HIDDEN COBRA actors, or when they open malicious email attachments.
During analysis of the infrastructure used by Joanap malware, the U.S. Government identified 87 compromised network nodes. The countries in which the infected IP addresses are registered are as follows:

Argentina

Belgium

Brazil

Cambodia

China

Colombia

Egypt

India

Iran

Jordan

Pakistan

Saudi Arabia

Spain

Sri Lanka

Sweden

Taiwan

Tunisia

Malware often infects servers and systems without the knowledge of system users and owners. If the malware can establish persistence, it could move laterally through a victim’s network and any connected networks to infect nodes beyond those identified in this alert.
Brambul malware is a brute-force authentication worm that spreads through SMB shares. SMBs enable shared access to files between users on a network. Brambul malware typically spreads by using a list of hard-coded login credentials to launch a brute-force password attack against an SMB protocol for access to a victim’s networks.Technical DetailsJoanap
Joanap is a two-stage malware used to establish peer-to-peer communications and to manage botnets designed to enable other operations. Joanap malware provides HIDDEN COBRA actors with the ability to exfiltrate data, drop and run secondary payloads, and initialize proxy communications on a compromised Windows device. Other notable functions include

file management,

process management,

creation and deletion of directories, and

node management.

Analysis indicates the malware encodes data using Rivest Cipher 4 encryption to protect its communication with HIDDEN COBRA actors. Once installed, the malware creates a log entry within the Windows System Directory in a file named mssscardprv.ax. HIDDEN COBRA actors use this file to capture and store victims’ information such as the host IP address, host name, and the current system time.Brambul
Brambul malware is a malicious Windows 32-bit SMB worm that functions as a service dynamic link library file or a portable executable file often dropped and installed onto victims’ networks by dropper malware. When executed, the malware attempts to establish contact with victim systems and IP addresses on victims’ local subnets. If successful, the application attempts to gain unauthorized access via the SMB protocol (ports 139 and 445) by launching brute-force password attacks using a list of embedded passwords. Additionally, the malware generates random IP addresses for further attacks.
Analysts suspect the malware targets insecure or unsecured user accounts and spreads through poorly secured network shares. Once the malware establishes unauthorized access on the victim’s systems, it communicates information about victim’s systems to HIDDEN COBRA actors using malicious email addresses. This information includes the IP address and host name—as well as the username and password—of each victim’s system. HIDDEN COBRA actors can use this information to remotely access a compromised system via the SMB protocol.
Analysis of a newer variant of Brambul malware identified the following built-in functions for remote operations:

Detection and Response
This alert’s IOC files provide HIDDEN COBRA IOCs related to Joanap and Brambul. DHS and FBI recommend that network administrators review the information provided, identify whether any of the provided IP addresses fall within their organizations’ allocated IP address space, and—if found—take necessary measures to remove the malware.
When reviewing network perimeter logs for the IP addresses, organizations may find instances of these IP addresses attempting to connect to their systems. Upon reviewing the traffic from these IP addresses, system owners may find some traffic relates to malicious activity and some traffic relates to legitimate activity.Impact

A successful network intrusion can have severe impacts, particularly if the compromise becomes public. Possible impacts include

temporary or permanent loss of sensitive or proprietary information,

disruption to regular operations,

financial losses incurred to restore systems and files, and

potential harm to an organization’s reputation.

Solution

Mitigation Strategies
DHS recommends that users and administrators use the following best practices as preventive measures to protect their computer networks:

Keep operating systems and software up-to-date with the latest patches. Most attacks target vulnerable applications and operating systems. Patching with the latest updates greatly reduces the number of exploitable entry points available to an attacker.

Maintain up-to-date antivirus software, and scan all software downloaded from the internet before executing.

Restrict users’ abilities (permissions) to install and run unwanted software applications, and apply the principle of least privilege to all systems and services. Restricting these privileges may prevent malware from running or limit its capability to spread through the network.

Scan for and remove suspicious email attachments. If a user opens a malicious attachment and enables macros, embedded code will execute the malware on the machine. Enterprises and organizations should consider blocking email messages from suspicious sources that contain attachments. For information on safely handling email attachments, see Using Caution with Email Attachments. Follow safe practices when browsing the web. See Good Security Habits and Safeguarding Your Data for additional details.

Disable Microsoft’s File and Printer Sharing service, if not required by the user’s organization. If this service is required, use strong passwords or Active Directory authentication. See Choosing and Protecting Passwords for more information on creating strong passwords.

Enable a personal firewall on organization workstations and configure it to deny unsolicited connection requests.

Response to Unauthorized Network AccessContact DHS or your local FBI office immediately. To report an intrusion and request resources for incident response or technical assistance, contact DHS NCCIC (NCCICCustomerService@hq.dhs.gov or 888-282-0870), FBI through a local field office, or FBI’s Cyber Division (CyWatch@fbi.gov or 855-292-3937).References

Cybersecurity researchers have identified that foreign cyber actors have compromised hundreds of thousands of home and office routers and other networked devices worldwide [1][2]. The actors used VPNFilter malware to target small office/home office (SOHO) routers. VPNFilter malware uses modular functionality to collect intelligence, exploit local area network (LAN) devices, and block actor-configurable network traffic. Specific characteristics of VPNFilter have only been observed in the BlackEnergy malware, specifically BlackEnergy versions 2 and 3.
The Department of Homeland Security (DHS) and the Federal Bureau of Investigation (FBI) recommend that owners of SOHO routers power cycle (reboot) SOHO routers and networked devices to temporarily disrupt the malware.
DHS and FBI encourage SOHO router owners to report information concerning suspicious or criminal activity to their local FBI field office or the FBI’s 24/7 Cyber Watch (CyWatch). Field office contacts can be identified at www.fbi.gov/contact-us/field. CyWatch can be contacted by phone at 855-292-3937 or by email at CyWatch@fbi.gov. Each submitted report should include as much informaiton as possible, specifically the date, time, location, type of activity, number of people, the type of equipment used for the activity, the name of the submitting company or organization, and a designated point of contact.Description

The size and scope of this infrastructure impacted by VPNFilter malware is significant. The persistent VPNFilter malware linked to this infrastructure targets a variety of SOHO routers and network-attached storage devices. The initial exploit vector for this malware is currently unknown.
The malware uses a modular functionality on SOHO routers to collect intelligence, exploit LAN devices, and block actor-configurable network traffic. The malware can render a device inoperable, and has destructive functionality across routers, network-attached storage devices, and central processing unit (CPU) architectures running embedded Linux. The command and control mechanism implemented by the malware uses a combination of secure sockets layer (SSL) with client-side certificates for authentication and TOR protocols, complicating network traffic detection and analysis.Impact

Negative consequences of VPNFilter malware infection include:

temporary or permanent loss of sensitive or proprietary information,

disruption to regular operations,

financial losses incurred to restore systems and files, and

potential harm to an organization’s reputation.

Solution

DHS and FBI recommend that all SOHO router owners power cycle (reboot) their devices to temporarily disrupt the malware.
Network device management interfaces—such as Telnet, SSH, Winbox, and HTTP—should be turned off for wide-area network (WAN) interfaces, and, when enabled, secured with strong passwords and encryption. Network devices should be upgraded to the latest available versions of firmware, which often contain patches for vulnerabilities.
Rebooting affected devices will cause non-persistent portions of the malware to be removed from the system. Network defenders should ensure that first-stage malware is removed from the devices, and appropriate network-level blocking is in place prior to rebooting affected devices. This will ensure that second stage malware is not downloaded again after reboot.
While the paths at each stage of the malware can vary across device platforms, processes running with the name "vpnfilter" are almost certainly instances of the second stage malware. Terminating these processes and removing associated processes and persistent files that execute the second stage malware would likely remove this malware from targeted devices.References